class Hashie::Mash

def default(key = nil)

be set to the value matching the key.
If key is a Symbol and it is a key in the mash, then the default value will
==== Alternatives

key:: The default value for the mash. Defaults to nil.
==== Parameters

Borrowed from Merb's Mash object. 
def default(key = nil) 
  if key.is_a?(Symbol) && key?(key.to_s) 
    self[key] 
  else 
    key ? super : super()
  end 
end